Some cassette accommodating cases into and from each of which a compact cassette can slidably be inserted and drawn in the longitudinal direction of the cassette accommodating case through a cassette insertion opening provided at one side portion of the case are disclosed in, for example, Japanese laid-open utility model publication No. 57-201675, Japanese laid-open utility model publication No. 58-148774, Japanese laid-open utility model publication No. 4-118388, and Japanese laid-open patent publication No. 4-311483.
Of the cassette accommodating cases according to the prior art, a cassette accommodating case disclosed in Japanese laid-open utility model publication No. 4-118388 will be described with reference to FIGS. 20 to 23.
FIG. 20 is a perspective view of the a cassette accommodating case with an upper surface plate thereof being partially cut away, showing an inside thereof. FIG. 21 is a perspective view of a compact cassette. FIG. 22 is a plan view of a cassette accommodating case with a cassette in its accommodated state being shown by a phantom line. FIG. 23 is a side view of the cassette accommodating case in its cassette accommodating state, seen from its cassette insertion opening.
An arrangement of the compact cassette will be described with reference to FIG. 21.
A compact cassette 30 has a pair of tape reels, not shown, rotatably housed in its cassette housing. Reel hub apertures 32a, 32b correspond to a pair of opening portions 31a formed through upper and lower surfaces of a cassette housing 30a and a pair of opening portions 32a formed therethrough. The compact cassette 30 has a trapezoid projected portion 33 forming a mouth of the cassette at its one side portion and also has a guide projection (usually also referred to as an ear portion) 34 at both side surfaces on the projection portion 33 side of the cassette housing.
The cassette accommodating case is formed of a plastic molded product. The cassette accommodating case has a cassette insertion opening 35 at its one side surface and has, in other portions, a flat-box shape formed of a bottom surface plate 36a, an upper surface plate 36b, left and right side surface plates 36c, 36d and a rear surface plate 36e. The compact cassette 30 is slidably inserted into and drawn from the cassette accommodating case through the cassette insertion opening 35 in the longitudinal direction. The bottom surface plate 36a and the upper surface plate 36b respectively have notch portions 35a, 35b on the sides of the cassette insertion opening 35. Therefore, when the compact cassette 30 accommodated in the cassette accommodating case is drawn therefrom, the compact cassette can be drawn by gripping cassette end portions exposed through the notch portions 35a, 35b as shown in FIG. 22.
The bottom surface plate 36a has two tab-shaped real stopper pieces 37a, 37b which can rise by their elastic forces and which are formed integrally therewith at positions corresponding to a substantially middle portion of the cassette insertion opening 35 at an interval in the depth direction. The reel stopper pieces 37a, 37b are faced in the direction perpendicularly to the depth direction. The interval between the reel stopper pieces 37a, 37b corresponds to an interval between the reel hub apertures 32a, 32b of the compact cassette 30.
The bottom surface plate 36a has receiving guides 38a, 38b projectingly formed at positions across the reel stopper pieces 37a, 37b so as to be thick and extended in the depth direction. The upper surface plate 36b also has receiving guides 39a, 39b projectingly formed so as to be thick and opposed to the receiving guides 38a, 38b, respectively (see FIG. 23).
Moreover, the bottom surface plate 36a and the upper surface plate 36b respectively have stopper pieces 40a, 40b and 41a, 41b in the vicinity of the cassette insertion opening 35 and at the outsides of the receiving guides 38a, 38b and 39a, 39b so as to be opposed to each other.
When the compact cassette 30 is inserted into the cassette accommodating case thus arranged through its cassette insertion opening 35 with its guide projection 33 being inserted first, the compact cassette elastically deforms and pushes down the reel stopper pieces 37a, 37b. However, when the cassette is inserted and reaches the deepest position of the cassette accommodating case, the reel stopper pieces 37a, 37b respectively correspond to the reel hub apertures 32a, 32b and hence rise again by their elastic forces. Then, the reel stopper pieces are respectively engaged with the reel hub apertures 32a, 32b to thereby prevent the reels from being rotated.
In a state that the compact cassette 30 is accommodated in the cassette accommodating case, since the receiving guides 38a, 38b and 39a, 39b projectingly formed from the bottom surface plate 36a and the upper surface plate 36b hold upper and lower surfaces of the cassette 30 except the projection portion 33, respectively, as shown in FIG. 23, the compact cassette 30 can stably be accommodated in the cassette accommodating case without being shaky.
Moreover, in the accommodated state of the compact cassette 30, as shown in FIG. 22, since the side edge portions of the projection portions 33 are engaged with stopper pieces 40a, 41a, the compact cassette 30 is prevented from being drawn from the cassette accommodating case.
The compact cassette 30 can be inserted into the above cassette accommodating case similarly as described above even in a state that it is inverted in the left and right directions. In this case, the side edge portions of the projection portions 33 of the compact cassette 30 are engaged with the other stopper pieces 40b, 41b, thereby the compact cassette being prevented from being drawn from the cassette accommodating case.
When the compact cassette 30 is drawn from the cassette accommodating case, the reel stopper pieces 37a, 37b are elastically deformed and pressed down to be disengaged from the reel hub apertures 32a, 32b. After the cassette is drawn therefrom, the reel stopper pieces 37a, 37b rise up again by their elastic forces.
Whenever the compact cassette 30 is inserted or drawn, the reel stopper pieces 37a, 37b are elastically deformed in the vicinity of their base portions and then pressed down. If the reel stopper pieces 37a, 37b are repeatedly and intensively bent and deformed, then fatigue in elasticity is caused in materials of the reel stopper pieces themselves and hence disables the reel stopper pieces to rise again. As a result, it becomes difficult for the reel stopper pieces to stop rotation of the reels thereafter.
If as a reel stopper of this kind there is employed a reel stopper member arranged such that, as shown in FIG. 24, two tab-shaped reel stopper pieces 43, 43 molded out of PP (polypropylene) are planted integrally on a base plate 42 and the base plate 42 are fixed by caulking on a bottom surface of the cassette accommodating case through a plurality of caulking apertures 42a, it is required to set a width of each of the reel stopper pieces 43, 43 substantially equal to an inside diameter of the reel hub aperture in order to prevent the reel from being rotated. This arrangement lowers operability of drawing the cassette because the reel stopper pieces are engaged with the reel hub apertures when the cassette is drawn from the cassette accommodating case.
While a relationship between the reel stopper pieces 43 and the reel hub apertures is important as described above, a height of each of the reel stopper pieces must be set substantially as high as an upper portion of the hub aperture in order to lock the reel hub apertures when the reel stopper pieces are engaged with and inserted into the reel hub apertures at their center portions. This arrangement leads to a fatal problem that when the cassette is deeply inserted into the cassette accommodating case, the reel stopper pieces are pressed down and prevented by edge portions of he hub apertures from rising in the hub apertures.
The above cassette accommodating case has a function to prevent the compact cassette 30 accommodated therein from being freely drawn therefrom by engaging side edge portions 33a of the projection portions 33 of the cassette 30 with the stopper pieces 40a and 41a or 40b and 41b projectingly formed on the bottom surface plate 36a and the upper surface plate 36b in the vicinity of the cassette insertion opening 35.
However, since the stopper pieces of this kind do not have elasticity themselves and hence the compact cassette 30 are slid rubbing surfaces of the projection portions 33 when being repeatedly inserted and drawn, there is then the problem that scratches are produced on the projection portions 33 and shavings are produced. In particular, if the friction of the stopper pieces with the projection portions 33 lowers the projecting heights of the stopper pieces, then a function of engagement of the stopper pieces with the projection portions 33 is lowered, which disables a function of preventing the compact cassette from being freely drawn from the cassette accommodating case.
Another mechanism for preventing a compact cassette from being freely drawn can be considered in which a stopper projection, not shown, is provided at a side surface wall of the cassette accommodating case and the stopper projection is engaged with a concave portion formed on the rear surface of the compact cassette of an erroneous erasure preventing click to thereby prevent the compact cassette from being freely drawn. In this case, since the stopper projection rubs the cassette when the cassette is inserted and drawn and hence the stopper projection becomes worn, it becomes impossible similarly as described above to prevent the cassette from being freely drawn.
The prevent invention is made to solve the above problems, and it is an object of the present invention to increase durability of the reel stopper pieces against deformation caused down when the cassette is inserted and drawn and hence the reel stopper pieces are pressed down and rise.